The aim of this project is to study the ability of membrane lipids to modulate ethanol action on cloned, large-conductance Ca++-dependent K+ (BK) channels. The drug activates BK channels, and this potentiation persists through a variety of increasingly simplified preparations. In this series of experiments, cloned BK channels will be incorporated into planar lipid bilayers, an approach which provides control of both the protein and lipid components of the system. It therefore allows a precise determination of the impact of lipid substitution on channel modulation, as well as a means to study known channel variants within identical lipid environments. Single channel records will be obtained and analyzed, to study the interplay of ethanol and membrane lipid composition in determined parameters of channel function such as open probability, dwell times, and conductance. Lipid substitutions are chosen based on literature demonstrating: effects on BK channel activity, effects on membrane fluidity, and adaptive changes in membrane composition in response to chronic ethanol exposure. Data generated in these studies will provide insight into the molecular mechanisms by which ethanol exerts its effect on ion channels. A molecular understanding of drug action is a necessary pre-requisite for a future understanding of ethanol effects on neuronal excitability and associated behavior.